Extrusion of higher alkyl sulphate salts



Patented June 18, 1940 UNITED STATES PATENT OFFICE EXTRUSION OF HIGHER ALKYL SULPHATE SALTS No Drawing. Application September 30, 1937, Serial No. 166,709

12 Glaims; (o1. 260-459) This invention relates to a process for the preparation of higher aliphatic hydrocarbon sulphates in needle form. It also pertains to the preparation of higher alkali metal alkyl sulphates in a suitable form for extrusion. Still more particularly it relates to the neutralization of higher alkyl hydrogen sulphates. v

It is an object of this invention to provide an improved method for the production of higher alkali metal alkyl sulphates in the form of needles which are free flowingand substantially dry. A further object is to prepare essentially dry alkali metal high molecular alkyl sulphates in a simple manner which eliminates expensive drying steps.

Another object is to obtain a neutralized product of the above type which can be extruded through a small opening. Other objects will appear hereinafter.

The prior art methods of neutralizing higher alkyl hydrogen sulphates have a number of disadvantages and the products are not suitable forv extrusion into thread or needle form. Thus essentially dry salts of alkyl hydrogen sulphates have been obtained by sulphating higher alcohols in the presence of nonaqueous solvents followed by neutralization with anhydrous bases. This process is expensive because solvents are required and their recovery is diiiicult. Higher alkyl hydrogen sulphates have been neutralized with dilute aqueous solutions of caustic soda at low temperatures and then dried. This drying involves considerable handling of the material and is expensive and difiicult to practice, Neutralization of alkyl hydrogen sulphates with concentrated solutions of caustic soda or with anhydrous alkali metal bases to produce essentially dry alkali metal alkyl sulphates have not been successful on a commercial scale because the heat of neutralization is so great that the temperature rises to a point where excessive hydrolysis of the alkyl hydrogen sulphates occurs unless solvents are employed. Essentially dry alkali metal alkyl sulphates have been made by reacting alkyl hydrogen sulphates with alkali metal halides. However, the corrosive conditions under which this method has been carried out is undesirable on a commercial scale.

The above and other objects are accomplished by this invention which comprises neutralizing higher alkylhydrogen sulphates with concentrated aqueous solutions of alkali metal bases in the presence of inert solid materials in'bulk form and extruding the neutralization mass into threads or needles. 'In more particular embodi- I 5 ments of the invention they are accomplished by neutralizing the sulphate esters in the above manner under reduced pressure.

Alkyl hydrogen sulphates which have been prepared by known methods, for example, by the. reaction of higher alcohols with chlorosulphonic 5 acid, are mixed with a mixture of a concentrated aqueous caustic soda solution with a solid diluent such as sodium sulphate. By virtue of the increased heat absorbing capacity secured by addition of the solid diluent an excessive rise in 10 temperature during the neutralization is prevented. The use of a solid diluent also makes the mass more bulky and, therefore, it has more surface which facilitates external cooling. Since a diluent is required for obtaining products with 16 standard active ingredient contents for commercial use, the use of a diluent for the dissipation of the heat of neutralization involves no added expense. 7 m

If it is desired to produce more concentrated alkali metal alkyl sulphates or products with minimum amounts of electrolytes, the neutralization'isaccomplished by mixing the alkyl hydrogen sulphates with concentrated caustic soda 1! solution under vacuum. ,By carrying out the v neutraligation under vacuum most of the small amount of water present in the caustic soda solution and that formed by neutralization distllls off at a temperature below the temperature where rapid hydrolysis of the alkyl hydrogen sul-"i phates occurs. In this manner most of the heat of neutralization is dissipated by vaporization of the water.

The invention will be further illustratedbut is not intended to be limited by the following"! examples in which the parts stated are. by weight:

Example I To 14 parts of an aqueous 50% caustic soda v to C. The mass becomes doughy and after it is thoroughly mixed it is extruded through I apertures of 0.025 inch in diameter. threads which extend from the apertures of the extrusion machine are cooled with a current of cold air. After cooling the threads become brittle and fall off, breaking intosmall needles as they strike the container in which they are collected; M

The"

' ing the neutralization rises only to 50 to 55 C.,

and if the neutralization is carried out without the solid diluent at atmospheric pressure the temperature rises to above- 100 C.

Ezrample To 43 parts of a 35% caustic soda solution in a mixer there is added over aperiod of about 15 minutes 100 parts of alkyl hydrogen sulphate derived as in Example I. During the neutralization the mixer is evacuated to about 15 mm., andwater distills out of the mixer. After distillation of the water from the mixer ceases the mass is extruded as in Example I. The product consists essentially of sodium alkyl sulphate with small amounts of sodium sulphate, water, and

unsulphated alcohols.

Example III To 37.5 parts of an aqueous 40% caustic soda solution and 100 parts of anhydrous sodium sulphate in a mixer, evacuated to about 25 mm., is added 100 parts alkyl hydrogen sulphate derived as in Example I. After no more liquid distills off under vacuum, the mass is extruded into thread form. The product contains about 50% sodium alkyl sulphate.

Example IV To 135 parts anhydrous sodium bicarbonate in a mixer, evacuated to about 25 mm., are added 100 parts of alkyl hydrogen sulphate derived as in Example'I. After mixing for about 1 hour the mass is extruded as in Example I. The product contains about 50% sodium alkyl sulphate.

. Example V To 20 parts 50% caustic soda solution, 22 parts trisodium phosphate (Na3PO4.1I-I2O), and 205 parts anhydrous sodium sulphate in a mixer, evacuated to about 25 mm., are added 100 parts of the unsaturated higher aliphatic hydrocarbon hydrogen sulphates obtained by sulphating the alcohols containing mostly 14 to 18 carbon atoms obtained from sperm oil. After the neutralization is complete the mass is heated to 6575 C.

until no more liquid distills off and then extruded. The product contains about 33% sodium alkyl sulphate.

This invention is limited only to the principle involved in the preceding examples and not to the particular materials or to the proportions of these materials given in the examples.

In Example I sodium sulphate is added to prevent too high a rise in temperature during the neutralization and also to obtain a standard product with about one-third active ingredients.

In place of sodium sulphate may be used many other diluents such as sodium chloride, sodium borate, sodium acetate, sodium bicarbonate, sodium sulphite, bentonite, sugar, and other salts of the alkali metals. Anhydrous bases such as anhydrous sodium carbonate may be used either under normal or reduced pressure conditions in one embodiment of this invention. The anhydrous base is used in quantities larger than those ,verted to monosodium phosphate.

desired to make bars or cakes.

theoretically required,'however, the excess base being an inert diluent. Other inert solid diluents may be incorporated if desired.

Part of the alkyl hydrogen sulphate in Example I is neutralized with caustic soda and the other part with trisodium phosphate. The alkaline materials are so adjusted that most of the trisodium phosphate is converted to disodium phosphate, a small amount being con- In this manner the alkalinity of the charge is automatically adjusted. It is, however, not necessary ple II the heat of neutralization is dissipated by vaporization of the water in the caustic soda solution and the water formed by neutralization. In Example IV part of the heat of neutralization is expended by vaporization of the water and part by heating the solid diluent.

For neutralization of the alkyl hydrogen sulphates, alkali metal bases or alkali metal salts which react alkaline may be used. Potassium hydroxide, potassium carbonate and bicarbonate, sodium carbonate and disodium phosphate are examples of other alkaline reagents which may be used for neutralization in the anhydrous form or in the form of concentrated aqueous solutions.

When caustic soda is used as the neutralizing solution the concentration should be above 25 B. and preferably above 35 B. Solutions of the other bases should be sufficiently concentrated so that no more water is introduced in the mass than the amount incurred by the use of a 25 B. caustic soda solution.

The vacuum required on the mixer will depend upon the temperature at which the alkyl hydrogen sulphates hydrolyze. By employing a high vacuum the boiling point of the Water in the neutralization mass is lowered and the temperature of the neutralization mass will rise only- Any of the sulphuric acid esters of the higher alcohols which are mentioned in U. S. Patents 1,968,793, 1,968,794, 1,968,795, and 1,968,797 may be neutralized by the methods described above. For manufacture of the alkali metal salts of the unsaturated alcohol sulphates in needle form the neutralization should be carried out under vacuum and/or the neutralization mass should be heated under vacuum in the mixer after the neutralization is complete in order to raise the softening temperature and improve the solubility of the needles obtained by extruding the neutralization mass. Small amounts of water and unidentified compounds are removed by this procedure. The solubility of the alkali metal salts of the saturated alkyl sulphates is also improved by evacuation during the neutralization. It is, however, not necessary to carry out the neutralization of the saturated alkyl hydrogen sulphates under vacuum or to heat the neutralization mass under vacuum to remove water, since the product is suitable for extrusion if the water content is below 5%.

The essentially dry neutralization masses obtained by the above methods can be extruded through very small apertures, less than .050 inch in diameter, or through large apertures if it is A drier and the labor involved in drying pastes are eliminated by this procedure and it is practical to neutralize the alkyl hydrogen sulphates in this manner on a commercial scale since excessive corrosion is not obtained.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it will be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims.

We claim:

1. The process which comprises neutralizing a higher aliphatic alcohol sulphuric acid ester under reduced pressure conditions with concentrated aqueous solution of an alkali metal base in the presence of an added water-soluble diluent which is solid at room temperature.

2. A process as set forth in claim 1 wherein the diluent is anhydrous sodium sulphate.

3. A process as set forth in claim 1 wherein the diluent is anhydrous sodium bicarbonate.

4. The process which comprises neutralizing a higher alcohol sulphuric acid ester under reduced pressure conditions with a concentrated aqueous solution of an alkali metal base in the presence of an added water-soluble diluent which is solid at room temperature, removing the volatile products from the reaction zone and then extruding the mass into products of small cross section.

5. The process of claim 4 in which a vacuum of less than 500 mm. is maintained.

6. The process of claim 4 in which a vacuum of 10 to 100 mm. is maintained.

'7. The process which comprises neutralizing a higher alcohol sulphuric acid ester under reduced pressure conditions with a concentrated aqueous solution of an alkali metal base in the presence of an added water-soluble diluent which is solid at room temperature, removing the volatile products from the reaction zone and then extruding the mass into products of small cross section when substantially all of the free water has been removed from the system.

8. The process which comprises neutralizing an alkyl hydrogen sulphate containing 8 to 24 carbon atoms under reduced pressure with a concentrated aqueous solution of an alkali metal base in the presence of an added water-soluble diluent which is solid at room temperature, removing the water and volatile products from the reaction zone and extruding the essentially dry mass into thread or needle form.

9. The process which comprises neutralizing an alkyl hydrogen sulphate containing 8 to 24 carbon atoms under reduced pressure with a concentrated aqueous solution of an alkali metal base in the presence of about to 40% by weight based upon the sulphate of an added watersoluble diluent which is solid at room temperature, removing the water and volatile products from the reaction zone and extruding the essentially dry mass into thread or needle form.

10. The process which comprises neutralizing a higher unsaturated aliphatic alcohol hydrogen sulphate with a concentrated aqueous caustic soda solution in the presence of an added watersoluble diluent which is solid at room temperature under reduced pressure conditions while removing water and Volatile products from the reaction zone and extruding the mass which does not contain more than 0.5% of water intothread or needle form.

11. In the process of obtaining higher alkali metal aliphatic hydrocarbon sulphates in essentially dry form suitable for extrusion, the step which comprises neutralizing the free acid esters with a concentrated solution of an alkali metal base containing an added Water-soluble diluent which is solid at room temperature while maintaining a high degree of vacuum thereon.

12. In the process of obtaining alkali metal higher aliphatic hydrocarbon sulphates in essentially dry form suitable for extrusion, the step which comprises neutralizing the corresponding free acid esters with a concentrated solution of an alkali metal salt which reacts alkaline, containing an added water-soluble diluent which is solid at room temperature under reduced pressure conditions.

CLYDE O. HENKE. ROLAND G. BENNER.

CERTIFICATE CE CORRECTION.

Patent No. 2,205,057. June 1 19M.

CLYDE 0.. HENKE, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, line 1414., for "15 parts". read '-75 parts"; and that the said Letters Patent should be read Evith this correction therein that the same may conform to the record of the case in the Patent Office,

Signed and sealed this 6th day of August, A. D. 191m.

Henry Van Arsdele, (Seal) Acting Commissioner of Patents. 

